In a computer system, a computer resource (hereinafter referred to just as a resource) such as processing capability of a CPU and storage capacity of a storage device preferably has a capacity appropriate for a system transaction. Accordingly, in a computer that can offer various services via a network, it is necessary to prepare an appropriate capacity according to the access amount or the change in access frequency.
Conventionally, as a method of adjusting the capacity of a computer system resource, for example, there was provided the method wherein, monitoring a real operating condition of the system, a person predicts when and which resources lack the capacity and adds required resources.
In addition, the configuration and setting of software and hardware in the server (sizing) required for satisfying the needs of the application was tested in a test environment before operation of the system by measuring the system load for each type of transaction according to an application and estimating the necessary capacity (capacity planning) (for example, See: “Tool for Capacity Planning”, [online], 6 Jun. 2003, Microsoft [searched in 28 Apr. 2004], <URL: http://www.microsoft.com/japan/msdn/net/bda/bdadotnetarch081.asp>). In this method, as a parameter in the test, a person estimated and inputted the number of processing transactions expected during real operation of the system.
Furthermore, in recent years, research has been performed on autonomic computing that endows a computer with features of “configuring”, “restoring”, “optimizing”, and “protecting” itself to make it autonomously work (for example, See: “Blueprint Relating to Autonomic Computing Architecture”, [online], April 2003, IBM Japan, [searched in 22 Aug. 2003], <URL: http://www-6. ibm.com/jp/autonomic/pdf/acwp-j.pdf>).
The capacity of the system can be adjusted using this technique. That is to say, having an additional resource ready in advance, this technique makes a computer itself to supplement the resource lacking in the real operation, using this additional resource.